/**
 * Marks the document as "JavaScript available".
 *
 * Every hidden state in this template — the scroll reveals, the collapsed
 * mobile menu, the blurred neighbours in the room rail — is written under
 * `html.js` in the stylesheet. If the scripts fail to load, that class is
 * never added and the page stays completely readable instead of showing
 * empty blocks.
 *
 * This file is loaded synchronously in <head>, before the first paint, which
 * is what prevents a flash of visible-then-hidden content.
 */
document.documentElement.classList.add("js");
